Copper-Catalyzed Asymmetric Kinugasa/Michael Addition Cascade Reactions for the Synthesis of Chiral Spiro β-Lactams.

A mild copper-catalyzed asymmetric Kinugasa/Michael addition cascade process is developed. The reaction of α, β-unsaturated ester-tethered propiolamides with nitrones provides an efficient protocol for the construction of functionalized chiral 2,6-diazaspiro[3.4]octane-1,5-dione products in satisfactory yields and with high enantio- and diastereoselectivities.

A transition-metal-free azide-alkyne cycloaddition/hydroamination cascade reaction for the construction of triazole-fused piperazin-2-ones.

A time-dependent, divergent synthesis of highly functionalized [1,2,3]triazolo[1,5-]pyrazin-4(5)-one (reaction time: 12 h) or 6,7-dihydro-[1,2,3]triazolo[1,5-]pyrazin-4(5)-one (reaction time: 2 h) scaffolds a cascade azide-alkyne cycloaddition/hydroamination protocol is reported. The transformation features good functional group compatibility, broad substrate scope, high atom economy and avoidance of the use of transition-metal catalysts.

An Alkyne-Isocyanide Cycloaddition/Boulton-Katritzky Rearrangement/Ring Expansion Reaction: Access to 9-Deazaguanines.

An alkyne-isocyanide [3 + 2] cycloaddition followed by a Boulton-Katritzky rearrangement and a ring expansion is demonstrated. Different from the typical Boulton-Katritzky rearrangement, which forms five-membered ring products, the rearrangement-ring expansion method provides a mild, efficient, and atom-economical access to fused 9-deazaguanine structures in high yields.

The Protective Effect of (-)-Tetrahydroalstonine against OGD/R-Induced Neuronal Injury via Autophagy Regulation.

Here, (-)-Tetrahydroalstonine (THA) was isolated from and investigated for its neuroprotective effect towards oxygen-glucose deprivation/re-oxygenation (OGD/R)-induced neuronal damage. In this study, primary cortical neurons were pre-treated with THA and then subjected to OGD/R induction. The cell viability was tested by the MTT assay, and the states of the autophagy-lysosomal pathway and Akt/mTOR pathway were monitored by Western blot analysis.

Harmol promotes α-synuclein degradation and improves motor impairment in Parkinson's models via regulating autophagy-lysosome pathway.

The abnormal accumulation of α-synuclein (α-syn) is a crucial factor for the onset and pathogenesis of Parkinson's disease (PD), and the autophagy-lysosome pathway (ALP) contributes to α-syn turnover. AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR) regulate autophagy by initiating the macroautophagy cascade and promoting lysosomal biogenesis via increased transcription factor EB (TFEB) activity. Hence, activation of AMPK-mTOR-TFEB axis-mediated autophagy might promote α-syn clearance in PD.

3'-Oxo-tabernaelegantine A (OTNA) selectively relaxes pulmonary arteries by inhibiting AhR.

Background: Pulmonary arterial hypertension (PAH), characterized by pulmonary artery constriction and vascular remodeling, has a high mortality rate. New drugs for the treatment of PAH urgently need to be developed.

Purpose: This study was designed to investigate the vasorelaxant activity of OTNA in isolated pulmonary arteries, and explore its molecular mechanism.

Hunzeylanines A-E, Five Bisindole Alkaloids Tethered with a Methylene Group from the Roots of .

Five novel bisindole alkaloids, hunzeylanines A-E (), with an unprecedented skeleton were isolated from the roots of . Compounds represent the first examples of akuammine-pleioarpamine-type bisindole alkaloids fused with a dihydropyran unit. Their structures including absolute configurations were established through comprehensive spectroscopic data analyses and computational calculation methods.

Hunterines A-C, Three Unusual Monoterpenoid Indole Alkaloids from .

Three new monoterpenoid indole alkaloids (MIAs), hunterines A-C (-), were isolated from Compound possesses a unique skeleton with an unprecedented azabicyclo[4.3.1]decane ring system.

Two New Flavonoids from the Nuts of .

Two new flavonoids, calquiquelignan M (), calquiquelignan N (), along with nine known compounds (-), were isolated from the nuts of (Palmae). The new structures, including absolute configurations, were established by a combination of spectroscopic data and electronic circular dichroism (ECD) calculation. The known compounds were identified by comparing their spectroscopic data with reported in the literature.

Three New Monoterpenoid Indole Alkaloids from Ervatamia pandacaqui.

Three new monoterpenoid indole alkaloids, ervapandine A (1), (3R)-hydroxyibogaine (3), 12-hydroxyakuammicine N(4)-oxide (6), along with four known ones, were isolated from the twigs and leaves of Ervatamia pandacaqui. The structures of the new alkaloids were elucidated by spectroscopic methods and sugar hydrolysis experiment. All of the compounds were evaluated for their cytotoxicity against three human cell lines.

Ervadivamines A and B, Two Unusual Trimeric Monoterpenoid Indole Alkaloids from Ervatamia divaricata.

Ervadivamines A (1) and B (2), two unprecedented trimeric monoterpenoid indole alkaloids, were isolated from Ervatamia divaricata. They are the first examples of vobasine-iboga-vobasine-type alkaloid with both C-C and C-N linkage patterns. Their structures including absolute configurations were fully accomplished by extensive spectroscopic analysis, single-crystal X-ray diffraction, and electric circular dichroism methods.